In GimpSpinButton, adjust the scroll step in response to modifiers:
normal scrolling uses the step increment, Ctrl uses the page
increment, and Shift scales the step increment down by the ratio
between the page and step increments (up to the minimal precision
of the spin button).
This applies to all spin buttons used in GIMP, including spin
scales.
(cherry picked from commit ac8bf47fa6)
When the "wrap" property of a GimpSpinButton is TRUE, wrap-around
out-of-range values entered through the spin-button's text entry,
instead of clamping them. Since we're using GimpSpinButton
everywhere since last commit, this applies to all our angle-entry
spin buttons (including spin scales).
(cherry picked from commit 8b3c7ae193)
GimpSpinButton is a drop-in replacement for (and a subclass of)
GtkSpinButton. Unlike GtkSpinButton, it avoids updating the
adjustment value when losing focus, unless the entry text has
changed. This prevents accidental loss of precision, when the
adjustment value can't be accurately displayed in the entry.
Note that libgimpwidgets already defines a (deprecated)
gimp_spin_button_new() function. This commit stays compatible with
the old function, by defining GimpSpinButton's _new() function as
gimp_spin_button_new_(), and defining a variadic
gimp_spin_button_new() macro, which expands to either the old or
the new function, based on the number of arguments, so that either
function can be used transparently as gimp_spin_button_new(). This
is all gone in master.
